Optical distance measurement system using solid state beam steering

ABSTRACT

An optical distance measuring system includes a first transmitter, a first solid state device, and a receiver. The first transmitter is configured to generate a first optical waveform. The first solid state device is configured to receive the first optical waveform and steer the first optical waveform toward a target object. The receiver is configured to receive the first optical waveform reflected off of the first target object and determine a distance to the first target object based on a time of flight from the transmitter to the first target object and back to the receiver.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 62/334,713, filed May 11, 2016, titled “3D DistanceMeasurements Using Micromirror Beam Steering And Orthogonal LightWaveforms,” which is hereby incorporated herein by reference in itsentirety.

BACKGROUND

Light Detection And Ranging (LiDAR, LIDAR, lidar, LADAR) is a systemthat measures the distance to a target object by reflecting a laserpulse sequence (a single narrow pulse or sequence of modulated narrowpulses) off of the target and analyzing the reflected light. Morespecifically, LiDAR systems typically determine a time of flight (TOF)for the laser pulse to travel from the laser to the target object andreturn either directly or by analyzing the phase shift between thereflected light signal and the transmitted light signal. The distance tothe target object then may be determined based on the TOF. These systemsmay be used in many applications including: geography, geology,geomorphology, seismology, transport, and remote sensing. For example,in transportation, automobiles may include LiDAR systems to monitor thedistance between the vehicle and other objects (e.g., another vehicle).The vehicle may utilize the distance determined by the LiDAR system to,for example, determine whether the other object, such as anothervehicle, is too close, and automatically apply braking.

Many LiDAR systems use a rotating optical measurement system todetermine distance information for objects in its field of view (FOV).The intensity of the reflected light is measured for several verticalplanes through a full 360 degree rotation. However, these systems havelimited angular and vertical resolution and require several watts ofpower to rotate the system.

SUMMARY

In accordance with at least one embodiment of the disclosure, an opticaldistance measuring system includes a first transmitter, a first solidstate device, and a receiver. The first transmitter is configured togenerate a first optical waveform. The first solid state device isconfigured to receive the first optical waveform and steer the firstoptical waveform toward a target object. The receiver is configured toreceive the first optical waveform reflected off of the first targetobject and determine a distance to the first target object based on atime of flight from the transmitter to the first target object and backto the receiver.

Another illustrative embodiment is an optical transmitting system foroptical distance measuring that includes a signal generator, a laserdiode coupled to the signal generator, and a solid state device. Thesignal generator is configured to generate a pulse sequence. The laserdiode is configured to generate an optical waveform that correspondswith the pulse sequence. The solid state device is configured to receivethe optical waveform and steer the optical waveform toward a targetobject.

Yet another illustrative embodiment is a method for determining adistance to a target object. The method includes generating a firstoptical waveform. The method also includes focusing the first opticalwaveform on a solid state device. The method also includes steering, bythe solid state device, the first optical waveform to a first targetobject. The method also includes receiving the first optical waveformreflected off of the first target object. The method also includesdetermining a distance to the first target object based on a time offlight of the first optical waveform.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of various examples, reference will now bemade to the accompanying drawings in which:

FIG. 1 shows an illustrative distance measuring system in accordancewith various examples;

FIG. 2 shows an illustrative distance measuring system in accordancewith various examples;

FIG. 3 shows an illustrative transmitting system for a distancemeasuring system in accordance with various examples;

FIG. 4 show an illustrative receiving system for a distance measuringsystem in accordance with various examples; and

FIG. 5 shows an illustrative flow diagram of a method for determining adistance to a target object in accordance with various examples.

NOTATION AND NOMENCLATURE

Certain terms are used throughout the following description and claimsto refer to particular system components. As one skilled in the art willappreciate, companies may refer to a component by different names. Thisdocument does not intend to distinguish between components that differin name but not function. In the following discussion and in the claims,the terms “including” and “comprising” are used in an open-endedfashion, and thus should be interpreted to mean “including, but notlimited to . . . .” Also, the term “couple” or “couples” is intended tomean either an indirect or direct connection. Thus, if a first devicecouples to a second device, that connection may be through a directconnection, or through an indirect connection via other devices andconnections. The recitation “based on” is intended to mean “based atleast in part on.” Therefore, if X is based on Y, X may be based on Yand any number of other factors.

DETAILED DESCRIPTION

The following discussion is directed to various embodiments of thedisclosure. Although one or more of these embodiments may be preferred,the embodiments disclosed should not be interpreted, or otherwise used,as limiting the scope of the disclosure, including the claims. Inaddition, one skilled in the art will understand that the followingdescription has broad application, and the discussion of any embodimentis meant only to be exemplary of that embodiment, and not intended tointimate that the scope of the disclosure, including the claims, islimited to that embodiment.

Optical distance measurement systems, such as LiDAR systems, maydetermine distances to various target objects utilizing the time offlight (TOF) of an optical signal (i.e., a light signal) to the targetobject and its reflection off a target object back to the LiDAR system(return signal). These systems may be used in many applicationsincluding: geography, geology, geomorphology, seismology, transport, andremote sensing. For example, in transportation, automobiles may includeLiDAR systems to monitor the distance between the vehicle and otherobjects (e.g., another vehicle). The vehicle may utilize the distancedetermined by the LiDAR system to, for example, determine whether theother object, such as another vehicle, is too close, and automaticallyapply braking.

As discussed above, many conventional LiDAR systems use a rotatingoptical measurement system to determine distance information for objectsin its FOV. The intensity of the reflected light is measured for severalvertical planes through a full 360 degree rotation. For example, theseconventional LiDAR systems may use a rotating set of transmit andreceive optics. For each scan plane, a light beam is transmitted andreceived at each angular position of the rotating system. When complete,a three dimensional (3D) image of the FOV may be generated. However,these systems have limited angular and vertical resolution and requireseveral watts of power to rotate the system. Therefore, there is a needto develop an optical distance measurement system that increases angularand vertical resolution while reducing power requirements.

In accordance with various examples, a distance measuring system isprovided in which a solid state device (e.g., a micromirror device, aphased array device, etc.) is configured to steer optical waveformswithin the FOV. Because a solid state device is used to steer theoptical beams, the system, unlike conventional distance measuringsystems, does not require a motor to rotate the system. Thus, powerrequirements of the system are reduced. Additionally, in an embodiment,multiple orthogonal optical waveforms may be simultaneously steered bythe solid state device, each to different locations and/or targetobjects within the FOV. Thus, the scan rate and the accuracy of thedistance measurements are increased.

FIG. 1 shows an illustrative distance measuring system 100 in accordancewith various examples. The distance measuring system 100 includes atransmitter 102, solid state devices 104 and 108, receiver 110, andcontroller 112. The transmitter 102 is configured to generate an opticalwaveform 152 by the controller 112. In some embodiments, the opticalwaveform 152 is a single tone (e.g., a continuous wave), a single tonewith phase modulation (e.g., phase shift keying), multiple tones withfixed frequencies (e.g., frequency shift keying), a signal withfrequency modulation over a frequency range (e.g., a chirp), and/or asignal with narrowband, pulse position modulation.

The solid state device 104 is configured to receive the optical waveform152 and steer the optical waveform toward target object 106. In someembodiments, the solid state device 104 is a single chip micromirrordevice (e.g., a digital micromirror device). In the micromirror deviceembodiments, the solid state device 104 has a surface that includesthousands, tens of thousands, hundreds of thousands, millions, etc.microscopic mirrors arranged in an array (e.g., a rectangular array).Each of the mirrors on the solid state device 104 are capable ofrotation, in some embodiments, by plus or minus 10 to 12 degrees. Inother embodiments, the mirrors of the solid state device 104 may berotated by more or less than plus or minus 10 to 12 degrees. In someembodiments, one or more electrodes (e.g., two pairs) control theposition (e.g., the amount of rotation) of each mirror by electrostaticattraction. To rotate the mirrors on the solid state device 104, therequired state for each mirror is loaded into a static random-accessmemory (SRAM) cell that is located beneath each mirror. The SRAM cell isconnected to the electrodes that control the rotation of a particularmirror. The charges in the SRAM cells then move each mirror to thedesired position. Controller 112 is configured to provide each SRAM cellwith the required charge, and thus, controls the position of each mirrorin the solid state device 104. Based on the position of each mirror, thesolid state device 104 directs the reflected light to form an opticalwaveform 152 (e.g., optical beam of light) that can be steered to adesired location within the FOV of the system 100. In other words, themirrors may be positioned to create diffraction patterns causing thebeam to steer in two dimensions to a desired location within the FOV. Ifthe desired location is target object 106, the solid state device 104steers the optical waveform 152 toward target object 106. While somepower is required to rotate the mirrors, the power required to rotatethese micromirrors is much less than the power required in conventionalsystems to rotate the entire set of optics within the distance measuringsystem.

In other embodiments, the solid state device 104 is a phased arraydevice using temperature to steer the optical waveform 152. In thesephased array device embodiments, the controller 112 controls thetemperature of each of a number of wave guides of the solid state device104. The wave guides provide optical paths to form the optical waveform152. By controlling the temperature of the specific wave guides, eachpath may be phase delayed. This design enables the solid state device104 to steer the optical waveform 152 in two dimensions to the targetobject 106.

In other embodiments, the solid state device 104 is a phased arraydevice using position to steer the optical waveform 152. In these phasedarray device embodiments, the controller 112 controls the linear orangular position of a number of reflective surfaces of the solid statedevice 104. The reflective surfaces provide optical paths to form theoptical waveform 152. By controlling the length and/or orientation ofthe optical paths, each path may be phase delayed. This design enablesthe solid state device 104 to steer the optical waveform 152 in twodimensions to the target object 106. In further embodiments, the solidstate device 104 may be any solid state device that is capable ofsteering optical waveform 152.

The optical waveform 152 reflects off of the target object 106. Thereflected optical waveform 152 is then received by the solid statedevice 108, and in a similar manner to solid state device 104, steeredto the receiver 110. Like the solid state device 104, the solid statedevice 108 receives control instructions from controller 112 toconfigure the solid state device 108 such that the reflected opticalwaveform 152 is steered to the receiver 110. In alternative embodiments,a single solid state device 104 may be utilized to both steer theoptical waveform 152 to the target object and to steer the reflectedoptical waveform 152 to the receiver 110. Additionally, in someembodiments, the receiver 110 receives the reflected optical waveform152 directly from the target object 106.

The receiver 110 is configured to receive the reflected optical waveform152 and determine the distance to the target object 106 based on the TOFfrom the transmitter 102 to the target object 106 and back to thereceiver 110. For example, the speed of light is known, so the distanceto the target object 106 is determined and/or estimated using the TOF.That is, the distance is estimated as

$d = \frac{c*{TOF}}{2}$where d is the distance to the target object, c is the speed of light,and TOF is the time of flight. The speed of light times the TOF ishalved to account for the travel of the light pulse to, and from, thetarget object 106. In some embodiments, the receiver 110, in addition toreceiving the reflected optical waveform 152 reflected off of the targetobject 106, is also configured to receive the optical waveform 152, or aportion of the optical waveform 152, directly from the transmitter 102.The receiver 110, in an embodiment, is configured to convert the twooptical signals into electrical signals, a received signal correspondingto the reflected optical waveform 152 and a reference signalcorresponding to the optical waveform 152 received directly from thetransmitter 102. The receiver 110 then, in an embodiment, performs acorrelation function using the reference signal and the received signal.A peak in the correlation function corresponds to the time delay of thereceived reflected optical waveform 152 (i.e., the TOF). The distancethen can be estimated using the formula discussed above. In otherembodiments, a fast Fourier transform (FFT) can be performed on thereceived signal. A phase of the tone then is used to estimate the delay(i.e., TOF) in the received signal. The distance then can be estimatedusing the formula discussed above.

FIG. 2 shows an illustrative distance measuring system 200 in accordancewith various examples. The distance measuring system 200 includestransmitters 102, 202, and 204, solid state device 104, and targetobjects 106, 206, and 208. The ellipsis between the transmitters 202 and204 indicates that there may be any number of transmitters, although,for clarity, only three are shown. Similarly, the ellipses between thetarget objects 206 and 208 indicates that there may be any number oftarget objects, although, for clarity, only three are shown.Transmitters 202-204 are, in an embodiment, similar to transmitter 102.For example, transmitter 202 is configured to generate an opticalwaveform 252, and transmitter 204 is configured is configured togenerate optical waveform 254. In some embodiments, the opticalwaveforms 252 and 254 are a single tone (e.g., a continuous wave), asingle tone with phase modulation (e.g., phase shift keying), multipletones with fixed frequencies (e.g., frequency shift keying), a signalwith frequency modulation over a frequency range (e.g., a chirp), and/ora signal with narrowband, pulse position modulation. In someembodiments, optical waveform 152 has a different wavelength than theoptical waveforms 252 and/or 254. Similarly, the optical waveform 252,in an embodiment, has a different wavelength than the optical waveforms152 and/or 254. Thus, the optical waveforms 102, 202, and 204 can havetwo or more wavelengths amongst the waveforms. In some embodiments, theoptical waveform 152 is modulated with a different modulation sequencethan the optical waveforms 252 and/or 254. Similarly, the opticalwaveform 252, in an embodiment, is modulated with a different modulationsequence than the optical waveforms 152 and/or 254.

In addition to receiving the optical waveform 152, the solid statedevice 104 is configured, in an embodiment, to receive the opticalwaveforms 252 and 254. In some embodiments, the transmitter 102 isconfigured to focus the optical waveform 152 onto a first region of thesolid state device 104. For example, the transmitter 102 can focus theoptical waveform 152 onto a region of micromirrors (i.e., a plurality ofmicromirrors) located on the solid state device 104. Similarly, thetransmitter 202 is, in an embodiment, configured to focus the opticalwaveform 252 onto a second region of the solid state device 104, and thetransmitter 204 is configured to focus the optical waveform 254 onto athird region of the solid state device 104. In some embodiments, thefirst, second, and third regions of the solid state device 104 arediscontinuous (i.e., they do not overlap). For example, the transmitter102 can focus the optical wave 152 onto a plurality of micromirrors, andthe transmitter 202 can focus the optical wave 252 onto a plurality ofmicromirrors that does not include any micromirrors that receives theoptical waveform 152.

The solid state device 104 is, as discussed above, configured to steerthe optical waveform 152 to target object 106. Additionally, the solidstate device 104, in an embodiment, is configured to steer opticalwaveform 252 to target object 206 and optical waveform 254 to targetobject 208. In some embodiments, the solid state device 104 isconfigured such that the first region that receives the optical waveform152 steers the optical waveform 152 toward the target object 106; thesecond region that receives the optical waveform 252 steers the opticalwaveform 252 toward the target object 206; and the third region thatreceives the optical waveform 254 steers the optical waveform 254 towardthe target object 208. For example, the controller 112 can configuremicromirrors on the solid state device 104 such that the micromirrors inthe first region are positioned to steer the optical waveform 152 towardthe target object 106; micromirrors in the second region are positionedto steer the optical waveform 252 toward the target object 206; andmicromirrors in the third region are positioned to steer the opticalwaveform 254 toward the target object 208. In this way, a single solidstate device may steer multiple optical waveforms to scan multipledifferent regions in the FOV simultaneously, thus increasing the scanrate of the system 100. While the above examples assume that the solidstate device 104 is a micromirror device, other solid state devices(e.g., a phased array device), would work similarly to steer multipleoptical waveforms toward multiple regions of interest in the FOV of thesystem 100. Additionally, in some embodiments, the optical waveforms152, 252, and 254 may be steered and reflected off of the same targetobject.

The receiver 110 is, in an embodiment, configured to receive each of theoptical waveforms 152, 252, and 254 after the waveforms have reflectedoff their respective target objects. For example, as discussed above,the receiver 110 is configured to receive reflected optical waveform 152after being reflected off target object 106. Similarly, the receiver 110is configured to receive the reflected optical waveform 252 after beingreflected off target object 206 and the reflected optical waveform 254after being reflected off target object 208. In some embodiments, eachreflected optical waveform 152, 252, and 254 is received by its ownreceiver. After the receiver 110 receives each reflected opticalwaveform 152, 252, and 254, in an embodiment, the receiver 110 isconfigured to determine the distance to each of the target objects 106,206, and 208 based on TOF as discussed above. Because, as discussedabove the optical waveforms 152, 252, and 254, and thus, the reflectedoptical waveforms are, in an embodiment, orthogonal to one another(i.e., have a different modulation sequence and/or a differentwavelength from one another), the receiver 110 can distinguish thedifferent received signals from one another. Thus, the receiver 110 iscapable of determining the distance to target object 106, target object206, and target object 208 even when the transmitters 102, 202, and 204transmit optical waveforms 152, 252, and 254 and/or the receiverreceives the reflected optical waveforms 152, 252, and 254simultaneously.

FIG. 3 shows an illustrative transmitting system 300 for distancemeasuring system 100 in accordance with various examples. Thetransmitting system 300 includes transmitter 102 and solid state device104. The transmitter 102, in an embodiment, includes a modulation signalgenerator 302, a signal generator 304, a transmission driver 306, alaser diode 308, and a set of optics 310. The modulation signalgenerator 302 is configured to provide a phase, frequency, amplitude,and/or position modulation reference signal. The signal generator 304 isconfigured to generate pulse sequences using the reference signal fromthe modulation signal generator 302. For example, the modulation signalgenerator 302, in an embodiment, is configured to generate a single tonesignal. In some embodiments, the modulation signal generator 302 isconfigured to generate a single tone (i.e. continuous wave), a singletone with phase modulation (e.g. phase shift keying), a single tone withamplitude modulation (e.g. amplitude shift keying), multiple tones withfixed frequencies (e.g. frequency shift keying), a signal with frequencymodulation over a narrowband frequency range (e.g. a chirp), and/or asignal with narrowband, pulse position modulation. The transmit driver306 generates a driving signal to drive an optical transmitter such aslaser diode 308. In other words, the modulation signal modulates theintensity of the light transmitted by laser diode 308 during the pulse.The signal generator 304 serves as a pulse sequence generator using themodulation signal as a reference. The set of optics 310 is configured todirect (e.g., focus) the optical waveform 152 (e.g., the modulated lightsignal) toward the solid state device 104. As discussed above, the solidstate device 104 is configured to steer the optical waveform 152 towarda region of interest that includes target object 106. Each of thetransmitters 202 and 204, in an embodiment, generates and directs itsrespective optical waveform (i.e., optical waveforms 252 and 254) in asimilar manner as transmitter 102. In some embodiments, a singleintegrated circuit (e.g., modulation signal generator 302, signalgenerator 304, and transmission driver 206) drives multiple laser diodesto transmit the optical waveforms 152, 252, and 254 as discussed above.

FIG. 4 show an illustrative receiving system 400 for distance measuringsystem 100 in accordance with various examples. The receiving systemincludes the receiver 110 and the solid state device 108. The receiverincludes, in an embodiment, a set of optics 410, two photodiodes 402 and412, two trans-impedance amplifiers (TIAs) 404 and 414, twoanalog-to-digital converters (ADCs) 406 and 416, and a receiverprocessor 408. As discussed above, in an embodiment, the reflectedoptical waveform 152 is received by the solid state device 108 andsteered toward the receiver 110. The set of optics 410, in anembodiment, receives the reflected optical waveform 152 from the solidstate device 108. In other words, the solid state device 108 steers thereflected optical waveform 152 toward the set of optics 410. The set ofoptics 410 directs (e.g., focuses) the reflected optical waveform towardthe photodiode 412. The photodiode 412 is configured to receive thereflected optical waveform 152 and convert the reflected opticalwaveform 152 into current received signal 452 (a current that isproportional to the intensity of the received reflected light). TIA 414is configured to receive current received signal 452 and convert thecurrent received signal 452 into a voltage signal, designated as voltagereceived signal 454, that corresponds with the current received signal452. ADC 416 is configured to receive the voltage received signal 454and convert the voltage received signal 454 from an analog signal into acorresponding digital signal, designated as digital received signal 456.Additionally, in some embodiments, the current received signal 452 isfiltered (e.g., band pass filtered) prior to being received by the TIA414 and/or the voltage received signal 454 is filtered prior to beingreceived by the ADC 416. In some embodiments, the photodiode 412 alsoreceives the reflected optical waveforms 252 and 254 and the receiver110 converts those waveforms into digital received signals in a similarmanner as reflected optical waveform 152 is converted into digitalreceived signal 456.

Photodiode 402, in an embodiment, receives the optical waveform 152, ora portion of the optical waveform 152, directly from the transmitter 102and converts the optical waveform 152 into current reference signal 462(a current that is proportional to the intensity of the received lightdirectly from transmitter 102). TIA 404 is configured to receive currentreference signal 462 and convert the current reference signal 462 into avoltage signal, designated as voltage reference signal 464, thatcorresponds with the current reference signal 462. ADC 406 is configuredto receive the voltage reference signal 464 and convert the voltagereference signal 464 from an analog signal into a corresponding digitalsignal, designated as digital reference signal 466. Additionally, insome embodiments, the current reference signal 462 is filtered (e.g.,band pass filtered) prior to being received by the TIA 404 and/or thevoltage reference signal 464 is filtered prior to being received by theADC 406. In some embodiments, the photodiode 402 also receives theoptical waveforms 252 and 254 directly from transmitters 202 and 204,respectively, and the receiver 110 converts those waveforms into digitalreference signals in a similar manner as optical waveform 152 isconverted into digital reference signal 466.

The processor 408 is any type of processor, controller, microcontroller,and/or microprocessor with an architecture optimized for processing thedigital received signal 456 and/or the digital reference signal 466. Forexample, the processor 408 may be a digital signal processor (DSP), acentral processing unit (CPU), a reduced instruction set computing(RISC) core such as an advanced RISC machine (ARM) core, a mixed signalprocessor (MSP), etc. The processor 408, in an embodiment, acts todemodulate the digital received signal 456 and the digital referencesignal 466. In some embodiments, the processor 408 also acts todemodulate the digital received signals corresponding to the reflectedoptical waveforms 252 and 254 and the digital reference signalscorresponding to the optical waveforms 252 and 254 received directlyfrom transmitters 202 and 204. Because the modulation sequence and/orthe wavelengths for the optical waveforms 152, 252, and/or 254 isdifferent from one another, the processor 408, because it knows themodulation sequence and/or wavelength for each of the optical waveforms152, 252, and/or 254, is capable of determining which signal is beingprocessed/analyzed.

The processor 408 then determines, in an embodiment, the distance to oneor more of the target objects 106, 206, and/or 208 by, as discussedabove, performing a correlation function using the reference signal andthe received signal. A peak in the correlation function corresponds tothe time delay of the received reflected optical waveform 152, 252,and/or 254 (i.e., the TOF). The distance to the target objects can beestimated using the formula discussed above. In other embodiments, anFFT is performed on the received digital signal 456 and/or the receiveddigital signals corresponding with the reflected optical waveforms 252and/or 254. A phase of the tone then is used to estimate the delay(i.e., TOF) in the received signals. The distance then can be estimatedusing the formula discussed above.

Because the distance measuring system 100 utilizes a solid state devicefor beam steering, power requirements are reduced when compared to theconventional system because the power needed by the solid state deviceto steer optical waveforms to scan an FOV is much less than the powerrequired in a motorized conventional system. Furthermore, because thesignals are, in an embodiment, modulated signals, scan rate androbustness can be increased because multiple laser diodes with their ownmodulation pattern and/or wavelengths may transmit and scan differentareas of the FOV simultaneously in the same environment withoutinterference with one another.

FIG. 5 shows an illustrative flow diagram of a method 500 fordetermining a distance to a target object in accordance with variousexamples. Though depicted sequentially as a matter of convenience, atleast some of the actions shown can be performed in a different orderand/or performed in parallel. Additionally, some embodiments may performonly some of the actions shown. In some embodiments, at least some ofthe operations of the method 500, as well as other operations describedherein, is performed by the transmitter 102 (including the modulationsignal generator 302, signal generator 304, transmission driver 306,laser diode 308, and/or the set of optics 310), the transmitters 202and/or 204, the solid state devices 104 and/or 108, and/or the receiver110 (including the set of optics 410, photodiodes 402 and/or 412, TIAs404 and/or 414, ADCs 406 and/or 416, and/or processor 408) andimplemented in logic and/or by a processor executing instructions storedin a non-transitory computer readable storage medium.

The method 500 begins in block 502 with modulating and/or generating afirst optical waveform and, in some embodiments, a second opticalwaveform. For example, the transmitter 102 generates optical waveform152 that is modulated with a specific modulation sequence and/or aspecific wavelength. The transmitter 202, in an embodiment, generatesoptical waveform 252 that is modulated with a specific modulationsequence that is different from the modulation sequence for opticalwaveform 152 and/or a specific wavelength that is different from thewavelength of optical waveform 152.

In block 504, the method 500 continues with focusing the first opticalwaveform, and in some embodiments, the second optical waveform on asolid state device. For example, the set of optics 310 is configured tofocus the optical waveform 152 onto the solid state device 104. A set ofoptics in transmitter 202 is configured to focus the optical waveform252 onto the solid state device 104 as well, in some embodiments,simultaneously as the optical waveform 152 is focused onto the solidstate device 104. In some embodiments, the optical waveform 152 isfocused on a first region of the solid state device 104 while theoptical waveform 252 is focused on a second region of the solid statedevice 104 that is discontinuous with the first region.

The method 500 continues in block 506 with steering the first opticalwaveform to a first target object. For example, the solid state device104 steers the optical waveform 152 to the target object 106. In block508, the method 500 continues with receiving the first optical waveformreflected off the first target object. For example, the receiver 110receives the reflected optical waveform 152 after being reflected offtarget object 106. In some embodiments, the solid state device 104and/or 108 steers the reflected optical waveform 152 to the receiver110. The method 500 continues in block 510 with determining the distanceto the first target object based on the TOF of the first opticalwaveform. For example, the receiver 110 converts the reflected opticalwaveform 152 into a received electrical signal, such as received digitalsignal 456, and determines the TOF of the reflected optical waveform 152based on a comparison between a reference signal corresponding to theoptical waveform 152 received directly from the transmitter 102 with thereceived electrical signal. The distance then is determined based on theTOF.

The method 500 continues in block 512 with steering the second opticalwaveform to a second target object. For example, the solid state device104 steers the optical waveform 252 to the target object 206. In block514, the method 500 continues with receiving the second optical waveformreflected off the second target object. For example, the receiver 110receives the reflected optical waveform 252 after being reflected offtarget object 206. In some embodiments, the solid state device 104and/or 108 steers the reflected optical waveform 252 to the receiver110. The method 500 continues in block 516 with determining the distanceto the second target object based on the TOF of the second opticalwaveform. For example, the receiver 110 converts the reflected opticalwaveform 252 into a received electrical signal and determines the TOF ofthe reflected optical waveform 252 based on a comparison between areference signal corresponding to the optical waveform 252 receiveddirectly from the transmitter 202 with the received electrical signalcorresponding to the reflected optical waveform 252. The distance thenis determined based on the TOF.

The above discussion is meant to be illustrative of the principles andvarious embodiments of the present disclosure. Numerous variations andmodifications will become apparent to those skilled in the art once theabove disclosure is fully appreciated. It is intended that the followingclaims be interpreted to embrace all such variations and modifications.

What is claimed is:
 1. A system, comprising: a first transmitterconfigured to produce a first optical waveform; a second transmitterconfigured to produce a second optical waveform; a solid state deviceoptically coupled to the first transmitter and to the secondtransmitter, the solid state device comprising first elements in a firstsolid state device region and second elements in a second solid statedevice region, the solid state device configured to: steer, by the firstelements, the first optical waveform toward a first region; and steer,by the second elements, the second optical waveform towards a secondregion; and a receiver configured to: receive a first reflection of thefirst optical waveform; receive a second reflection of the secondoptical waveform; determine a first distance based on the firstreflection of the first optical waveform; and determine a seconddistance based on the second reflection of the second optical waveform.2. The system of claim 1, wherein the receiver is configured to receivethe first reflection of the first optical waveform simultaneously withreceiving the second reflection of the second optical waveform.
 3. Thesystem of claim 1, wherein: the first transmitter includes: a firstsignal generator configured to produce a first pulse sequencecorresponding with the first optical waveform; and a first laser diodeconfigured to produce the first optical waveform; and the secondtransmitter includes: a second signal generator configured to generate asecond pulse sequence corresponding with the second optical waveform;and a second laser diode configured to produce the second opticalwaveform.
 4. The system of claim 3, wherein the first pulse sequence andthe first optical waveform have a first wavelength and the second pulsesequence and the second optical waveform have a second wavelength, thefirst wavelength being different from the second wavelength.
 5. Thesystem of claim 3, wherein the first pulse sequence and the firstoptical waveform are modulated with a first modulation sequence and thesecond pulse sequence and the second optical waveform are modulated witha second modulation sequence, the first modulation sequence beingdifferent from the second modulation sequence.
 6. The system of claim 3,wherein: the first transmitter further includes first optics configuredto focus the first optical waveform from the first laser diode onto thefirst solid state device region; the second transmitter further includessecond optics configured to focus the second optical waveform from thesecond laser diode onto the second solid state device region; and thefirst solid state device region being discontinuous with the secondsolid state device region.
 7. The system of claim 1, wherein the solidstate device is further configured to: receive the first reflection ofthe first optical waveform; and steer the first reflection of the firstoptical waveform toward the receiver.
 8. The system of claim 1, whereinthe solid state device is a first solid state device, the system furthercomprising a second solid state device configured to: receive the firstreflection of the first optical waveform; and steer the first reflectionof the first optical waveform toward the receiver.
 9. The system ofclaim 1, wherein the first optical waveform has a single tone, a singletone with phase modulation, multiple tones with fixed frequencies, asignal with frequency modulation over a frequency range, or a signalwith narrowband pulse position modulation.
 10. The system of claim 1,further comprising: a third transmitter optically coupled to the solidstate device, the third transmitter configured to produce a thirdoptical waveform; wherein the solid state device is further configuredto: receive, by third elements in a third solid state device region, thethird optical waveform; and steer the third optical waveform toward athird region; and wherein the receiver is further configured to: receivea third reflection of the third optical waveform in the third region;and determine a third distance based on the third reflection of thethird optical waveform.
 11. The system of claim 1, wherein the solidstate device is a digital micromirror device.
 12. A system, comprising:a first light source configured to produce a first optical waveformresponsive to a first pulse sequence; a second light source configuredto produce a second optical waveform responsive to a second pulsesequence; and a solid state device optically coupled to the first lightsource and to the second light source, the solid state device comprisingfirst elements in a first solid state device region and second elementsin a second solid state device region, the solid state device configuredto: steer, by the first elements, the first optical waveform toward afirst region; and steer, by the second elements, the second opticalwaveform toward a second region.
 13. The system of claim 12, furthercomprising optics configured to focus the first optical waveform fromthe first light source onto the first solid state device region.
 14. Thesystem of claim 13, wherein the first solid state device region isdiscontinuous from the second solid state device region.
 15. The systemof claim 12, wherein the first optical waveform has a first wavelengthand the second optical waveform has a second wavelength, the firstwavelength being different from the second wavelength.
 16. The system ofclaim 12, wherein the first optical waveform is modulated with a firstmodulation sequence and the second optical waveform is modulated with asecond modulation sequence, the first modulation sequence beingdifferent from the second modulation sequence.
 17. The system of claim12, further comprising: a first signal generator configured to producethe first pulse sequence; and a second signal generator configured toproduce the second pulse sequence.
 18. The system of claim 12, whereinthe solid state device is a digital micromirror device.
 19. A methodcomprising: producing, by a transmitter, a first optical waveform;steering, by first elements in a first solid state device region of asolid state device, the first optical waveform to a first region;producing, by the transmitter, a second optical waveform; and steering,by second elements in a second solid state device region of the solidstate device, the second optical waveform to a second region.
 20. Themethod of claim 19, wherein the first optical waveform has a firstwavelength, the second optical waveform has a second wavelength, and thefirst wavelength is different from the second wavelength.
 21. The methodof claim 19, further comprising: modulating the first optical waveformwith a first modulation sequence; and modulating the second opticalwaveform with a second modulation sequence; wherein the first modulationsequence is different from the second modulation sequence.
 22. Themethod of claim 19, further comprising: receiving, by a receiver, afirst reflection of the first optical waveform; receiving, by thereceiver, a second reflection of the second optical waveform;determining, by the receiver, a first distance based on the firstreflection of the first optical waveform; and determining, by thereceiver, a second distance based on the second reflection of the secondoptical waveform.